Mobile telephony systems such as GSM systems generally provide a short message service (SMS) by which a mobile user can send and receive short alphanumeric (“text”) messages of several tens of characters. Thus, for example, the GSM standard provides a “Mobile Terminating Short Message Service, Point to Point” (SMS-MT/PP) for the reception of short messages and a “Mobile Originating Short Message Service, Point to Point” (SMS-MO/PP) enabling a mobile user to send a short message to another party, such as another mobile user. Mobile-originating short messages are generally created using a keypad of the mobile device concerned whilst mobile terminating short messages will generally be presented to the recipient via a display of the receiving mobile device.
As regards the architecture of the mobile network needed to support short message services, due to the simplicity and brevity of the short messages concerned, the messages do not require the use of a traffic channel of the mobile network for their transfer, and are, instead, carried by control or management channels. Typically, the network will have an associated short message service centre (SM-SC) which interfaces with the network through specific mobile switching centres acting as SMS gateways. Thus, a mobile-originating messages is passed from a mobile device via a mobile switching centre to the SM-SC, whilst mobile-terminating short messages are passed from the SM-SC via a mobile switching centre to the target mobile device. The SM-SC itself can be provided with a wide range of service functionalities for storing and handling short messages; thus, for example, the SM-SC will generally store incoming mobile-terminating messages until the target mobile device is live to the network and able to receive messages, whilst for mobile-originating messages which are not intended or another mobile device, the SM-SC may provide for conversion of the messages into e-mail for sending on via an e-mail system.
Because of the fact that short messages do not use a traffic channel and generally take up little overhead, the operator charges for using SMS are relatively low. This has made SMS a popular service, particularly with younger persons. However, one problem experienced by the mobile user when using SMS is that the process of generating a short message is generally very tedious because of the restricted nature of the user input interface (a small keypad) provided on most mobile phones. Thus, since the number of keypad keys is less than the number of alphanumeric characters available, double, triple or even higher multiple keying is normally required for each character.
Because voice output is a very convenient way for a recipient to receive messages, particularly when the recipient is already visually occupied (such as when driving a vehicle) or where the recipient is visually impaired, systems are available for converting text messages into speech output. U.S. Pat. No. 5,475,738 describes one such system for converting e-mails to voice messages and U.S. Pat. No. 5,950,123 describes a system specifically adapted for converting SMS messages to speech output.
Of course, interpretation issues arise when effecting conversion of text to speech and, in particular, problems can arise with acronyms and other character combinations which have meanings to a restricted group. SMS messages in particular abound with all sorts of short-form character combinations (such as “cul8r” for “see you later”) that are difficult for a text-to-speech converter to handle because such character combinations are non-standard and quick to emerge (and disappear). Another example are so-called “smilies” which are character combinations that supposedly form a graphical depiction of an emotion (thus, the character combination: :->represents a smiling face, often used to imply humour); how a smilie should be handled by a text-to-speech converter is far from clear.
Apart from the conversion of message text to speech, little else is done to enhance the audio presentation of text messages though in this context it may be noted that the use of melodies to announce message arrival is well known, the melodies being either downloaded to the receiving device or locally composed (see, for example, U.S. Pat. Nos. 5,739,759 and 6075,998). It is also well known to use an audio mark-up language to mark-up information pages, such as web pages, in order to specify certain characteristics of audio presentation of such pages. In the same context, the use of audio style sheets has also been proposed (see U.S. Pat. No. 5,899,975).
It is an object of the present invention to provide improved ways of presenting text messages in audio form.